Migrants get off a federal bus on Monday at the Greyhound station in Phoenix. / Michael Chow, The Arizona Republic

by Daniel González, The Arizona Republic

by Daniel González, The Arizona Republic

PHOENIX -- The door of the Department of Homeland Security bus opened and about 40 undocumented immigrants from Central America staggered out into the ovenlike, 110-degree heat.

Almost all the migrants were women traveling with young children, some as young as 2 months old. They looked tired and beaten down, having spent weeks traveling through Central America and Mexico trying to cross the U.S. border illegally.

The somber scene was suddenly shattered by a woman yelling almost gleefully.

As the release of undocumented immigrants from Central America at the Greyhound Lines Inc. bus station in Phoenix continued into a second week, dozens of community volunteers such as Whitmore have mobilized a grassroots effort to provide humanitarian assistance.

Most of the migrants, who were apprehended in Texas, are not staying in Arizona. After being dropped off at the bus station, they board buses for other cities across the country.

Still, their release, which started on Memorial Day, has drawn fierce criticism - from members of Congress concerned the migrants will now disappear into the U.S. and from humanitarian groups concerned the migrants are being dumped at bus stations without food, water and other basic necessities.

In response, growing numbers of community volunteers have been showing up at the bus station in Phoenix daily, handing out bottles of water, slices of pizza, burritos, hot sandwiches and other food as the migrants are dropped off.

The volunteers also have set up a large aid station at one end of the bus station with tables filled with bottles of aspirin, cold medicine, tooth brushes, mouthwash, deodorant, diapers, sanitary napkins and other necessities.

They also have brought in boxes of used clothing and shoes.

On Monday, Faustina Pablo, 29, from Guatemala, picked through piles of children's clothing for her daughter, Jeydi, 8, minutes after being dropped off at the station.

Like virtually all the other migrants, Pablo had been released by Immigration and Customs Enforcement on humanitarian parole with instructions to report to ICE once she reaches her destination elsewhere in the U.S. Pablo was headed to Oakland, Calif., to reunite with a brother.

Interviews with nearly a dozen other migrants at the bus station indicated they were headed to cities all over the U.S., including Houston, Los Angeles, Baltimore, Miami and Nashville.

To help them arrange travel, some of the volunteers lend the migrants their cellphones so they can call relatives in other cities and arrange for them to pay for their bus tickets. Other volunteers help translate as the migrants pick up their tickets.

And for migrants who can't catch a bus until the next day, volunteers are taking them home for the night and providing them with a place to sleep, said Whitmore, a volunteer with the Phoenix Restoration Project, which provides assistance to detained and released migrants.

"These are people who have been released on humanitarian parole," Whitmore said, adding that providing them with assistance is "absolutely the right thing to do."

But not everyone is happy about their release.

On Monday, Arizona Gov. Jan Brewer sent a letter to President Barack Obama attacking his administration's decision to transport illegal immigrants from Texas to Arizona.

"I am deeply concerned about this troubling policy and the adverse impact on the illegal aliens, as well as to Arizona," Brewer wrote.

She also raised concerns about the migrants' safety.

"I remind you that the daytime temperatures in Arizona during this time of year are regularly more than 100 degrees," Brewer said. "Consequently, this federal operation seems to place expedience over basic humanitarian concerns."

On Tuesday, Arizona's two U.S. senators, John McCain and Jeff Flake, also sent a letter to Homeland Security Secretary Jeh Johnson demanding more information about the release of migrants at the bus stations, including how many have been transported to Arizona, why they are being released and how the DHS will respond to migrants who disappear or commit crimes after their release.

Although the release has drawn criticism, the Obama administration has deported more immigrants than administrations under any other president. In the first five years of Obama's presidency, the U.S. deported more than 2 million people.

Jacqueline Wasiluk, a Border Patrol spokeswoman in Washington, D.C., could not say Tuesday whether any additional migrants have been flown from Texas to Arizona, or whether the Border Patrol plans to transport more migrants to Arizona.

She reiterated that the migrants are being transported to Arizona because the Border Patrol does not have the manpower to handle a surge in undocumented immigrants from Central America being apprehended in the Rio Grande Valley of southern Texas.

While illegal-immigrant apprehensions in the Tucson Sector, once the nation's busiest, have plummeted in recent years, they have soared in southern Texas, which is now the main entry point for illegal border crossers.

In fiscal 2013, the Border Patrol recorded 154,453 apprehensions in the Rio Grande Valley, up 58 percent from the previous year.

Carlos Vélez-Ibáñez, chairman of Arizona State University's department of transborder studies, said a combination of crime, violence, poverty, gangs, drug cartels, corruption, economic problems and government instability is driving growing numbers of Central Americans to attempt to enter the U.S. illegally.

"These places are falling apart," Vélez-Ibáñez said.

All the migrants interviewed at the Greyhound bus station said they were from Guatemala, El Salvador or Honduras.

Honduras has the highest homicide rate in the world, according to an April report by the U.N. Office on Drugs and Crime.

El Salvador ranks fourth and Guatemala fifth.

But there may be another reason why so many migrants from Central America are attempting to cross the border illegally.

Several migrants said news stations in their home countries have been reporting that parents traveling with children are more likely to be released even if caught crossing the border illegally.

"That is what they are saying on the news, that if you travel as a woman with a child, there is an opportunity to get in," said Paulina Say, 29.

She was waiting to board a Greyhound bus to travel to Miami, where she said her husband has been living in the U.S. illegally for seven years working in a restaurant.

Say said she traveled by bus from her home in Totonicapan, Guatemala, through Mexico with her 6-year-old son, Mario.

Say said that once she reached Reynosa, a border city in Mexico across from Hidalgo, Texas, she paid a smuggler to ferry her and her son across the Rio Grande in an inflatable boat. Soon after, she was caught by the Border Patrol.

When U.S. immigration authorities in Texas loaded her onto a plane, Say said, she thought she was being flown back to Guatemala. Instead, she was flown to Arizona and released with a piece of paper instructing her to report to the ICE office in Miami at 9 a.m. on June 17.